BONN A goal to halve planet-warming carbon emissions by 2050, similar to an aim Japan is urging G8 leaders to agree next month, would add $45 trillion to global energy bills, the International Energy Agency said on Tuesday.
"It's a lot of money," IEA analyst Peter Taylor told a meeting on the fringes of a climate conference in Germany, previewing the agency's Energy Technology Perspectives report to be published in Japan on Friday.
"It implies a completely different energy system," he said.
For example, electricity from renewable sources such as hydropower and the wind would reach close to half all power production, compared to 18 percent now, Taylor told Reuters.
Scientists say that the world must brake and reverse annual increases in greenhouse gas emissions to avoid catastrophic climate change including rising seas and more extreme weather.
Japan last week urged leaders of the Group of Eight rich nations to set a global target to halve greenhouse gases by 2050, when they meet at a G8 summit in Toyako, northern Japan, next month.
The IEA took 2005 as its base level in calculating the cost of halving emissions of the commonest manmade greenhouse gas carbon dioxide by 2050 -- a very ambitious goal which it hadn't previously estimated.
That would require an extra $45 trillion investment in energy supply and demand through 2050 compared to a baseline of business as usual, said the energy adviser to 27 rich nations.
Recent high energy costs due to record oil prices have hurt motorists, farmers and fishermen, triggering protests in Europe.
The IEA identified 17 key technologies that would be required to achieve the 2050 target -- on the supply side these included carbon capture and storage, which involves burying carbon emissions from coal plants underground, and is currently untried on a commercial scale on grounds of expense.
On the energy demand side it required adoption of barely tested hydrogen fuel cell technologies in vehicles.
However, even if the 2050 target were reached, halving carbon emissions by mid-century could still result in long-term carbon dioxide concentrations in the air of about 450 parts per million, the report said.
That may exceed safe levels according to a definition by the EU and projections by the UN's panel of climate scientists, the
(Reporting by Gerard Wynn, Editing by Jon Boyle)